Hydroseeding on Frozen Ground

When we picture hydroseeding in our mind’s eye, we automatically think about someone out there with a pumper on a sunny spring day, or a balmy fall one. We don’t usually picture someone bundled up in a thick parka, a wool hat and gloves, spraying ground that’s rock-hard and cold as ice, or buried under drifts of white snow.

Many hydroseeding contractors pack their machines away once the weather turns bitter. Some, however, keep on working. Some of them even think that winter is one of the best seasons for applying seed.

Douglas Holmgren is one of those.

He’s president and founder of Turf Blasters, Inc., a hydroseeding company that also does hydro-feeding and sprayon erosion control blankets for residential, commercial and government clients.

He’s also president of the Penn Hills, Pennsylvania-based International Association of Hydroseeding Professionals (IAHP).

“A lot of people think that spring is the best time to seed,” says Holmgren. “But I would challenge that and say that the dormant season is actually better.”

He says that a major misconception on the part of consumers (and many contractors) is that there are only two good “windows,” spring and fall, for seeding, and outside of that, you just can’t do it. “But you can,” he insists. “We get wonderful results from hydroseeding in the heat of July and August, as well as what we call the dormant season,” otherwise known as winter.

By the way, this isn’t some guy in the Sunbelt talking. Holmgren’s business is based in Sioux Falls,
South Dakota. Turf Blasters hydroseeds all over the country, and
regularly works in our northernmost states, North Dakota, Wisconsin and
Minnesota among them.

“What
we look for up here is that first frost,” he says. “It’s a good
indicator that we’re safe for dormant seeding. Then, unless we get a
fluke warm-up, that seed’s not going to germinate until spring. It’ll
just lie there, and the snow’ll come down and pack on top of it. Come
spring, the slowly melting snow gives a perfect watering to that seed.”
The snow, in fact, functions as a natural irrigation system.

There’s
another benefit to dormant-season seeding, says Holmgren, and that’s
getting a head start on weeds. Seed, especially native seed, will
germinate and flourish before weeds appear, so you’re not in competition
with them.

The grass
will start germinating as soon as the snow starts melting off, when the
ground temperature reaches about 60 degrees. “That seed starts popping
right away, and gets pretty well established about the same time as the
weeds are just starting to germinate,” Holmgren adds.

Tim
Grenanco is owner and president of American Hydro Seeding,
headquartered in Warren, Michigan. He also does dormant-season seeding
for a large number of clients. “We seed right up until we have to
winterize our tanker,” he says. “Cold weather could freeze the pipes and
cause thousands of dollars in damage to our equipment. But, for the
right job, we will come out of ‘retirement.’” For example, one
particular chain of retail stores has been a reliable customer. Before
the chain can get a certificate of occupancy for a new location, the law
requires that the site be hydroseeded. The company “doesn’t care what
it costs; it just has to get done,” no matter what time of year it is.

Kevin
Huber, owner and president of Challenger Construction Corporation in
Clearwater, Kansas, is another contractor who doesn’t find anything odd
about hydroseeding in the winter. “A lot of people broadcast seed in the
winter. When I was growing up, we just threw fescue seed on top of
snow, and waited for the snow to take it down.”

“Once
the ground’s frozen, and you know it’s not going to warm up until the
spring, I don’t see any reason why you can’t do it. The seed’s not going
to germinate in that one day while you’re spraying.”

One
caveat: cold-weather seeding does seem to work better with natives.
Non-native seed, if it gets a bit warm, has a tendency to say, ‘It’s
spring; time to germinate.’ Natives are going to be more likely to lay
dormant and not pop up during a warm winter week. “You don’t have to
worry about them as much as some of the turf-type grasses,” says Huber.

Seeds can take the cold

Unlike
that old, forgotten box of pizza rolls behind the ice cube trays, seed
doesn’t suffer from “freezer burn.” As Joe Bilskemper, owner of La
Crosse-based Western Wisconsin Hydroseeding has found, seed is very
durable. “It’s tough; it’ll lay there over the winter and won’t do
anything.”

Holmgren
says he doesn’t experience any real seed loss doing winter seeding, but
then he does tend to put down a bit more seed for an extra safety
margin. For a new lawn installation, instead of the recommended four to
six pounds of seed per thousand, he usually puts down 8.3 pounds per
thousand.

“That’s our
policy,” he says, “year ‘round, regardless of season. It’s a lot cheaper
to put down those two extra pounds per thousand than to have to come
back and refill the machine, plus pay for labor, insurance, gas—all
those things over again—when we could be at a new job, making new
money.”

Rainstorms
don’t usually wash seed away, either. Grenanco sometimes has to reassure
customers of that. “I’ll get calls after storms, people saying, ‘My
seed washed away!’ I tell them, ‘It’s underneath the mud; you just can’t
see it. Wait six weeks. If it doesn’t grow, I’ll come back out.’ But I
usually don’t have to.”

A
greater threat to seed is a sudden warm spell. “If the seed starts to
establish, and infant grass starts growing, and then gets hit with a hard frost, that’s where
we’re going to lose it,” says Holmgren. The justemerged juvenile grass
isn’t sturdy enough to support itself through that process.

One
problem you won’t have in the winter is dryout, normally a major
concern, according to Bilskemper. “You tell people to keep the seed damp
once it’s down, but they don’t. Once that seed pops out of the kernel,
out of the seed sheath, you can’t let it sit there and bake in the sun;
it’s going to dessicate (dry out). But we don’t worry about that in the
colder weather so much.” The ‘natural irrigation system’ comes to the
rescue, once again.

Don’t neglect prep

Just
as with any other type of seeding or sodding, the top inch or two of
soil should be roughed up and then leveled and graded before
hydroseeding. If the ground is prepped and ready, Holmgren says he can
seed all winter long. “Unfortunately, in areas that get this cold, the
ground literally freezes to the point where you can’t cup it, till it,
disc it or in any way grade it.”

Holmgren
says that if more builders knew that they could have dormant-season
seeding done, they’d get that ground prepped while they’re doing the
exteriors, instead of leaving it for spring. “Then, when the ground
freezes, it’ll stay that way; you won’t have to worry about rain or wind
erosion, because it’s all frozen in place.”

“We
can seed, even in December, when it’s below freezing,” says Bilskemper.
“It can work, as long as the soil is loosened. Somebody has to get in
there with a drag and break it up a little bit. We need to be able to
blast a little of the seed into the soil.”

Possible pitfalls

Special
equipment or attachments aren’t needed for winter spraying. “But there
are some things you need to be aware of when you’re using the machine in
cold, freezing or potentially freezing weather,” cautions Jeff Clouser,
general manager of Epic Manufacturing, Greenwood, Delaware. “You’ll
need to winterize the machine.”

And,
you’ll need to do it every night. Winterizing isn’t just something
you’ll do at the end of the fall season, but whenever a seeder has been
out in the cold, spraying.

“The
key is to drain all of the water out of the machine,” says Clouser. “A
lot of contractors will hook up an air line so they can blow out the
hoses. I usually recommend putting some windshieldwiper fluid or RV
antifreeze down in the pump, so that if any water does collect in the
bottom, it’s not going to freeze and split the pump housing.”

A
hydroseeder’s brass ball valves are very susceptible to damage from
freezing, and these machines usually have three to five of these valves.
Clouser recommends “that you open and close those valves three or four
times, to get the water out of them.”

Here’s
why: each of the ball valves rotates inside a cavity. Water can become
trapped in the cavity behind a ball valve and freeze. If you don’t
rotate the ball three or four times, you might not clear all the water
out of the cavity.

After
that, “We recommend leaving that valve halfway open,” Clouser said.
“That way, if there’s still a little bit of water in there, it can
escape.” Water expands when it freezes, so providing this “escape hatch”
lessens the risk of splitting that ball valve.

Obviously,
the best thing would be to bed your hydroseeders down every night in a
nice, cozy, heated garage. Most contractors don’t have that luxury,
however, especially at jobsites.

Hoses
can get very rigid in the cold. “Contractors are very ingenious,”
Clouser quips. “I’ve seen them take blankets or tarps and tent off the
area where the pump and hose reel is with bungee cords. Then, they’ll
run a flex line off of the exhaust pipe, and direct the exhaust under
the tarps to keep the pump warm, and the hoses loose and pliable and
easy to maneuver.” (Just don’t stick your head under the tarp while the
engine’s running!) Black rubber hose is less affected by cold
temperatures, and remains a bit more pliable. There’s also “clear-braid”
hose. This type is made of two clear layers of polyethylene, with a
nylon braid woven between.

One
advantage of clear-braid is that it’s lighter weight, and seethrough;
if you get a clog you can easily spot it. However, it gets very stiff
and rigid in the cold. It’s also more prone to degradation by UV rays.

There
does come a point where it’s just too cold to spray, Holmgren says, or
you risk freezing a hydroseeder’s pipes. “As long as the temperature is
above 25 to 27 degrees, I can spray,” he says.

The
key is to keep the water flowing. Holmgren knows a little trick to help
that: he’ll throw in some extra tackifier to lower the freezing point.
Instead of 32 degrees, the chemicals in the tackifier make it so water
won’t freeze until the temperature hits 24 degrees. That gives him six
degrees of wiggle room before the slurry hardens.

But
not all tackifiers are created equal, as Holmgren discovered. A couple
of years ago, he decided to try a new formulation. Things looked very
good after doing some dormant-season seeding of 45 homes at a new
housing development. “When we laid the hydromulch down, it wasn’t freezing outside; we got a nice application of 2,000 pounds per acre.”

Then
came the rain—or what began as rain, anyway. As it grew darker and
colder, the rain turned to sleet, then snow. Under the downspouts of the
houses, water flowed underneath the mats of mulch, and froze.

“The
mulch wasn’t bonded to the ground anymore,” said Holmgren. “Water got
underneath it, and the mulch floated on top of it.” The water froze into
an ice sheet, and the mulch came up off the ground, still bonded to
itself, but not to the soil.

This
turned the mulch into a flaky crust that could be peeled off like
pieces of paper-mache. As the wind picked up, it ripped off big two- to
three-foot-wide strips of mulch and seed. Holmgren was forced to go back
and respray. He’s still not certain what caused the tackifier to behave
like that, but suspects it may have contained an acrylic that reacts
badly to cold weather.

The moral of this story is, if you’re going to experiment with something new, don’t do it on a job.

One
more tip: Huber suggests that if it’s getting close to winter, and
you’re doing a warm-season dormant planting, such as a native grass,
it’s a good idea to also put in a cool-season cover crop. He uses
sterile wheat grass, an annual rye, or oats.

The
purpose of this is twofold— to slow erosion, and to help the soil. “If
the cover crop gets killed by the winter, it’s not that big a deal. The
warm-season grasses are what you’re really going for.”

Downtime dollars

Holmgren
says that contractors who don’t seed in the winter are missing out on
extra revenue. “A lot of guys up here will quit hydroseeding in
September. What if they kept going into November? They could have
another month’s worth of work.”

Instead
of quitting in the fall, Holmgren says, “We just keep working. We know
that the next spring, there’s going to be a few sites that we’ll have to
touch up.

But I’d rather go touch up those half-dozen or so properties than give up the thirty others that’ll come out fine.”

Seeding
frozen ground isn’t only possible; in some situations, it may even be
preferable. So think about it…dormant-season dollars are just as green
as all the others.

In many ways, we are fortunate that, in our chosen profession, we are able to help people when certain disasters occur: the tornadoes in Missouri, Oklahoma, Louisiana and Georgia, the flooding in Louisiana, the snows in the northeastern part of the country, the rain in California, and the snow in Colorado....

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